NETROM over TCP

Introduction

This is an experimental system to send Netrom traffic over a TCP connection instead of the usual ax.25 links. This is primarily intended for use over radio modems where the user interface is TCP (such as "New Packet Radio" but can also be used as an alterntive to AX/IP and AX/UDP over the Internet. Currently only INP3 routing is supported on these links

Configuration

As this is using TCP one end of the Link must be defined as a Server (listening for connections) and the other as a Client (making connections).

All connections have to be defined in the ROUTES: section of the bpq32.cfg file. These need to use the new format (see ROUTES: Configuration) with a new field TCP specifing the remote host and port. The normal port is 53119 but can be changed if necessary

Server End:
CALL=GM8BPQ-5, PORT=2, QUALITY=1, INP3=1, TCP=0.0.0.0:53119

Clent End:
CALL=G8BPQ-9, PORT=2, QUALITY=1, INP3=1, TCP=192.168.1.64:53119

The connection uses your Telnet Port, so set the number of that port in the PORT= field. At the server end you also need to enable listening using the NETROMPORT directive in the TelnetServer configuration, eg NETROMPORT=53119

Monitoring

As the monitoring system is designed for ax.25 traffic a dummy ax.25 header is added locally before passing a packet to the monitoring system. This consists of an I frame with From and To calls set but NR and NS always set to zero.

Protocol Details

The NETROM Packet is sent over a TCP connection in following format:

struct NRTCPMsg
{
	short Length;				// Including header
	char Call[10];				// of sending Node
	unsigned char PID;
	char Packet[1024];
};

The current implementation supports INP3 only. It doesn't have a mechanism to send NODES broadcasts.